To produce formwork for the upper floors of cavity floors, it is known to use as expendable shuttering panel-like shuttering elements. Indeed, it is also known to use a synthetic plastics shuttering film provided with blocked-out portions which form the bearer feet by which the shuttering foil is supported on a lower floor. Flowable flooring composition is applied onto the shuttering film and flows into the upwardly-open bearer feet shapes, where it hardens and forms the bearer feet (German Offenlegungsschriften 31 03 632, 32 01 085, and 33 17 683). Such shuttering films with integrally moulded bearer feet, to be filled with flooring composition, are unstable to the extent that it is not possible for anyone to walk on the structure during installation. Furthermore, a variety of heights of cavity flooring cannot be produced with these shuttering films.
It is also already known to use square shuttering sheets with downwardly angled-over corners which fit into tubular bearer feet, the height of which can be adjusted by means of setscrews (German Gebrauchsmuster 84 04 767.4). The shuttering sheets or panels are provided with upwardly-angled edge parts at which they are clamped by means of special clamping sections. The cost of production and installation of a cavity floor produced by means of such shuttering sheets is relatively high. Furthermore, at the corner zones of the panels there are a large number of potential leakage points where the flooring composition can flow into the cavity of the double floor. Adjustment of the carrier feet by means of setscrews disposed at their bottom ends is difficult.
Finally, the state of the art also includes shuttering panels provided with integrally moulded hollow studs which constitute the means of connecting the vertically adjustable bearer feet (German Patent 34 34 872). The pot-shaped bearer feet are fitted frictionally in telescopic fashion on the hollow studs, with no holes on the bottom of the studs through which the flooring composition might pass. Pouring the flooring composition into the bearer feet is problematical since any enclosed air cannot escape. Thus the stability of the upper floor is questionable.